Evaluation of the immunization effects of needle-free injection for four common porcine vaccines.

With increasing concerns about food safety and animal welfare, as well as to support the development of large-scale and intensive animal husbandry, needle-free injection (NFI) technology has been widely used in vaccination and drug treatment. Therefore, this study evaluated the effects of two live vaccines (CSFV and PRRSV) and two inactivated vaccines (PCV and FMDV) delivered by NFI and needle injection (NI) in pigs. The average CSFV and PRRSV antibody levels in pigs were higher for NFI than for NI at immunization doses of 0.5 and 0.8, and the antibody conversion rate was higher for NFI at both doses. Regarding inactivated vaccines, the antibody level for FMDV was lower for NFI than for NI, and NFI was also linked to a lower antibody conversion rate. Conversely, antibody production following vaccination with PCV was higher for NFI than for NI at the same dose. In general, NFI did not significantly affect physiological parameters, such as body temperature and weight gain. Concerning the immunization effect, NFI showed comparable or superior immunogenicity for three of the four than NI. This study provides technical support and reference for the use and promotion of novel immunization modalities.